Answer:
Step-by-step explanation:
All those words! Just use math.

Write the left side of the given expression as N/D, where
N = sinA - sin3A + sin5A - sin7A
D = cosA - cos3A - cos5A + cos7A
Therefore we want to show that N/D = cot2A.
We shall use these identities:
sin x - sin y = 2cos((x+y)/2)*sin((x-y)/2)
cos x - cos y = -2sin((x+y)/2)*sin((x-y)2)
N = -(sin7A - sinA) + sin5A - sin3A
= -2cos4A*sin3A + 2cos4A*sinA
= 2cos4A(sinA - sin3A)
= 2cos4A*2cos(2A)sin(-A)
= -4cos4A*cos2A*sinA
D = cos7A + cosA - (cos5A + cos3A)
= 2cos4A*cos3A - 2cos4A*cosA
= 2cos4A(cos3A - cosA)
= 2cos4A*(-2)sin2A*sinA
= -4cos4A*sin2A*sinA
Therefore
N/D = [-4cos4A*cos2A*sinA]/[-4cos4A*sin2A*sinA]
= cos2A/sin2A
= cot2A
This verifies the identity.
Answer:

Step-by-step explanation:
we know that
In an <u><em>Arithmetic Sequence</em></u> the difference between one term and the next is a constant, and this constant is called the common difference
we have

Let

we have that



so
The common difference is equal to 9
We can write an Arithmetic Sequence as a rule:

where
a_n is the nth term
a_1 is the first term
d is the common difference
n is the number of terms
Find the 38th term of the arithmetic sequence
we have
substitute the values



Answer:
A biconditional statement is a combination of a conditional statement and its converse written in the if and only if form. Two line segments are congruent if and only if they are of equal length. ... A biconditional is true if and only if both the conditionals are true. there??
Step-by-step explanation:
Answer:
0.278
Step-by-step explanation:
Given that Nuri joins a game for a car. The rule is that Nuri pick one key from box either A, B, or C. A box has two keys but only one can be used. B box has three keys but only one can be used. C box has two keys but none of them can be used.
Each box is equally likely to be selected.
In other words

If A is selected then probability of winning is using the correct key out of two keys i.e. 0.5
If B is selected then probability of winning is using the correct key out of three keys i.e. 0.333
If c is selected then probability of winning is using the correct key out of two keys i.e. 0.00
So the probability that Nuri can win the car
= 